1. Field of the Invention
The present invention relates to a gripping assembly for use in a transfer press machine, and, more particularly, to a piston-cylinder assembly that performs the clamping activity on workpiece material transferred into the handling area of a fixed jaw assembly.
2. Description of the Related Art
Gripping mechanisms installed in conventional transfer press machines are typically provided in the form of a pair of spaced-apart jaw members. Material such as metal sheets or other workpiece elements are fed or otherwise transferred by known carrier systems into the gripping space defined between the jaw members. The workpiece is secured by effecting relative movement between the jaw members until both jaw members are brought into contacting engagement with the workpiece in a manner sufficient to firmly hold it in place. Subsequent transfer of the workpiece takes place by releasing the jaw members from their clamping arrangement.
Repositioning of the jaw members into a clamping arrangement may be accomplished using a variety of actuating mechanisms. In one conventional system, the jaw members may be hingedly coupled to one another such that their relative orientation may be changed by pivoting one jaw member with respect to the other or by pivoting both jaw members. Alternatively, one or both of the jaw members may be slidably attached to a guiding frame structure which facilitates vertical displacement of the jaw members using a linear drive assembly. Conventional transfer presses therefore implement the clamping activity by suitably displacing one or both of the jaw members.
According to the present invention there is provided a gripping device for use in a transfer press machine comprising a jaw assembly that includes an upper jaw member and a lower jaw member disposed in fixed spaced-apart relationship to one another. The jaw members have a clamping space defined therebetween which receives a workpiece during a desired clamping activity. The gripping device further includes a piston-cylinder assembly having a cylinder element mounted on the upper jaw member at an upper surface thereof and a piston element reciprocatingly housed within the cylinder element. The upper jaw member is provided with a bore passageway formed therethrough that opens into the,clamping space. The piston-cylinder assembly is suitably mounted on the upper jaw member such that the piston element is disposed in axial registration with the bore passageway, enabling the piston element to be displaceable therein and extensible into the clamping space. An actuating mechanism preferably provided in the form of a pneumatic pressurizing device controllably pressurizes the piston-cylinder assembly in order to effectuate a displacement of the piston element sufficient to establish a clamping arrangement in which the workpiece is securably held between the lower jaw member and piston element. The holding pressure is released by relieving the pressurization level of the piston-cylinder assembly, which causes the piston element to retract into the cylinder housing until the next clamping activity begins. In one preferred form of the gripping device, there is provided a plurality of piston-cylinder assemblies (and corresponding bore passageways formed in the upper jaw member) to enable multiple clamping points to be selectively maintained on the workpiece.
The invention, in one form thereof, comprises a gripper assembly for use in handling a workpiece. The gripper assembly includes a jaw assembly comprising a first jaw member and a second jaw member disposed in fixed spaced-apart relationship to one another and defining a clamping space therebetween. At least one of the first jaw member and second jaw member includes at least one bore passageway formed therethrough which opens into the clamping space. The gripper assembly further includes at least one piston-cylinder assembly which respectively comprises a cylinder element and a piston element associated therewith. The piston element is operatively displaceable within a respective bore passageway associated with the jaw assembly and is extensible into the clamping space to enable selective engagement with the workpiece operatively disposed therein. There is further provided a means for operatively actuating the at least one piston-cylinder assembly.
The actuating means, in one form thereof, further comprises a pneumatic pressurization assembly.
One advantage of the present invention is that the gripper assembly provides a uniquely different form of clamping activity vis-a-vis conventional arrangements, namely by having a piston element reciprocatingly travel through the fixed upper jaw member into clamping arrangement with the fixed lower jaw member, as compared to the conventional approach of moving the jaw members toward one another.
Another advantage of the present invention is that the gripper assembly eliminates the need for any drive mechanisms attached to the jaw assembly since the jaw members are disposed in fixed spaced-apart relationship to one another.
A further advantage of the invention is that the actuating mechanism needed to effectuate the gripping action involves a simplified construction requiring only a pneumatic pressurization device, as distinguished from conventional arrangements that utilize more drive-type components and coupling pieces.
A yet further advantage of the invention is that the gripper assembly minimizes the number of parts needed to implement the clamping arrangement (i.e., the movable piston element secures the workpiece against the stationary lower jaw member), thereby providing a highly reproducible and precise clamping action.